Ramsauer-Townsend minimum in methane — modified effective range analysis

摘要: Electron-scattering cross sections in methane are analysed the very-low energy region. The correspondence between integral elastic, elastic differential and momentum transfer is checked via a novel approach to modified effective range theory, order determine depth position of Ramsauer-Townsend minimum. Phase shifts two lowest partial waves obtained explicitly parameterized by four coefficients with physical meaning scattering lengths ranges. Using recent experiments on vibrational performed over an extended (0–180°) angular comparing several theories, agreement within 10% has been experimental total present summed (elastic + vibrational) whole 0.1–2.0 eV range. An additional check for consistency done using two-term Boltzmann analysis derive electron diffusion coefficients. Calculated drift velocities transversal at 0–10 Td reduced electric field agree 5% experiments.